Targets for the Antiviral and Antitumor Activities of Nucleoside,Nucleotide and Oligonucleotide Analogues

Abstract

The following targets can be considered in the development of antiviral agents: (i) DNA polymerase via dThd kinase, (ii) S-adenosylhomocysteine hydrolase; and in the development of antitumor agents: (iii) dTMP synthetase and (iv) protein synthesis via the 2–5A pathway.     

Light and electron microscopical demonstration of concanavalin A and wheat-germ agglutinin binding sites by use of antibodies against the lectin or its label (peroxidase)

Summary Three straining protocols for the ultrastructural visualization of concanavalin A (ConA) and wheat germ agglutinin (WGA) binding sites were applied to samples of nervous tissue embedded in Lowicryl K4M. The hypothalamo-neurohypophysial neurosecretory system was chosen for this investigation because it has two major neuronal populations, one secreting vasopressin, whose precursor is glycosylated, and the other secreting oxytocin whose precursor form is not glycosylated.The series of incubations of the tissue sections for the three protocols were: Protocol 1: i) non labeled ConA or WGA; ii) ConA or WGA antibody; iii) protein A-gold; Protocol 2: i) pre-prepared WGA-anti-WGA complex; ii) protein A-gold; Protocol 3: i) peroxidase-labeled ConA or WGA; ii) anti-peroxidase; iii) protein A-gold.The three methods allowed to detect fine differences in the distribution of sugar residues. This, in turn, made it possible to distinguish vasopressin granules containing precursor forms from those containing processed precursor.At the light microscopic level the three methods were successfully applied to paraffin and 1-m methacrylate sections by using a second antibody, PAP complex and the diaminobenzidine reaction.Supported by Grant I/63 476 from Stiftung Volkswagenwerk, Federal Republic of Germany and Grant S-85-39 from Dirección de Investigaciones, Universidad Austral de Chile. The authors wish to acknowledge the technical help of Genaro Alvial and Elizabeth     

Galvanotaxis of human granulocytes

The galvanotactic response of human granulocytes was investigated theoretically and experimentally. The basic results are: (i) The granulocytes move towards the anode. (ii) The directed movement has been quantified by two different polar order parameters-the McCutcheon index and the average of cos . (iii) The polar order parameters are a function of the applied electric field (= dose-response curve). (iv) The inverse of the galvanotactic constant of migrating cells (analogous to the Michaelis-Menten constant) has a value of-0.2±0.03 V/mm. (v) The galvanotactic response of granulocytes is a non-cooperative process with a cooperativity coefficient of 1±0.2. (vi) The galvanotactic constant is a function of pH. (vii) The protein essential for the galvanotactic response is very likely a G-protein.     

Hypo-osmotic stimulation of active Na+ transport in frog muscle: Apparent upregulation of Na+ pumps

Summary The purpose of this work was to determine if hypotonicity, in addition to the stimulation of active Na⁺ transport (Venosa, R.A., 1978,Biochim. Biophys. Acta 510:378–383), promoted changes in (i) active K⁺ influx, (ii) passive Na^– and K⁺ fluxes, and (iii) the number of³H-ouabain binding sites.The results indicate that a reduction of external osmotic pressure () to one-half of its normal value (=0.5) produced the following effects: (i) an increase in active K⁺ influx on the order of 160%, (ii) a 20% reduction in Na⁺ influx and K⁺ permeability (P _K), and (iii) a 40% increase in the apparent density of ouabain binding sites. These data suggest that the hypotonic stimulation of the Na⁺ pump is not caused by an increased leak of either Na⁺ (inward) or K⁺ (outward). It is unlikely that the stimulation of active Na⁺ extrusion and the rise in the apparent number of pump sites produced by hypotonicity were due to a reduction of the intracellular ionic strength. It appears that, at least in part, the stimulation of active Na⁺ transport takes place whenever muscles are transferred from one medium to another of lower tonicity even if neither one was hypotonic (for instance =2 to =1 transfer). Comparison of the present results with those previously reported indicate that in addition to the number of pump sites, the cycling rate of the pump is increased by hypotonicity. Active Na⁺ and K⁺ fluxes were not significantly altered by hypertonicity (=2).     

Characterization of a plasma membrane H+-ATPase from the extremely acidophilic algaDunaliella acidophila

Summary Dunaliella acidophila is an unicellular green alga which grows optimally at pH 0–1 while maintaining neutral internal pH. A plasma membrane preparation of this algae has been purified on sucrose density gradients. The preparation exhibits vanadatesensitive ATPase activity of 2 mol P_i/mg protein/min, an activity 15 to 30-fold higher than that in the related neutrophilic speciesD. salina. The following properties suggest that the ATPase is an electrogenic plasma membrane H⁺ pump. (i) ATP induces proton uptake and generates a positive-inside membrane potential as demonstrated with optical probes. (ii) ATP hydrolysis and proton uptake are inhibited by vanadate, diethylstilbestrol, dicyclohexylcarbodiimide and erythrosine but not by molybdate, azide or nitrate. (iii) ATP hydrolysis and proton uptake are stimulated by fussicoccin in a pH-dependent manner as found for plants plasma membrane H⁺-ATPase. Unusual properties of this enzyme are: (i) theK _m for ATP is around 60 M, considerably lower than in other plasma membrane H⁺-ATPases, and (ii) the ATPase activity and proton uptake are stimulated three to fourfold by K⁺ and to a smaller extent by other monovalent cations. These results suggest thatD. acidophila possesses a vanadate-sensitive H⁺-ATPase with unusual features enabling it to maintain the large transmembrane pH gradient.     

Responses of γ-aminobutyrate receptor from rat brain: Similarity of different preparation methods; muscimol induced desensitization and chloride exchange

Summary Chloride-36 exchange into three different membrane vesicle preparations from rat brain homogenate was followed. The different preparations all contained the same sealed vesicular components characterized by their rates of chloride exchange. The GABA-mediated³⁶Cl^– exchange in all the preparations occurred in two phases shown to be mediated by two distinguishable receptors present in the activity ratio of 51 as previously described (Cash, D.J., Subbarao, K. 1987.Biochemistry 26:7556, 7562). Reported differences do not result from differences in the membrane preparations used or from the use of a GABA-mimetic instead of GABA, but from experimental differences. The preparations compared were made with mild or vigorous homogenization and with different extents of purification from solutes or membrane components: (i) a synaptoneurosome preparation, (ii) a Ficoll gradient preparation, and (iii) a washed P₂ preparation. In each preparation the same four populations of membrane vesicles were characterized by their³⁶Cl^– influx rates: (i) a major population (40–50%) (t _1/2=1.4 min), (ii) a slower exchanging major population (40–55%) (t _1/2=24 min), (iii) a minor population (5–12%) containing active GABA receptor and having the GABA-independent permeability of the slower exchanging population, and (iv) a very small exchange (2%) (t _1/20.2 sec). The GABA-independent³⁶Cl^– exchange processes were kinetically first order. The relative quantities of the different vesicle populations varied slightly with the preparation and purification technique. The identity of these components, observed in the different preparations, was attributed to the vesicle formation being dependent on the morphology and properties of the membrane rather than the preparation method. The soluble brain extract was GABA-mimetic with the two observed receptors, causing channel opening and desensitization. But little washing of the membrane was required to observe the function of both receptors. Muscimol was GABA-mimetic with both receptors. With muscimol, channel opening occurred at 2.6-fold lower concentrations while desensitization was unaltered relative to GABA. This is additional evidence that these responses are mediated by different pairs of binding sites. The dependence of desensitization rate on muscimol concentration indicated that there are two binding sites mediating desensitization, as described with GABA.     

Deducing the lateral distribution of proteins in lipid bilayer membranes

We consider four models of the lateral distribution of proteins in lipid bilayer membranes and study the fraction of lipids which are adjacent to at least one protein (adjacent lipids) and how this quantity depends upon protein concentration. The models are (i) hard hexagons free to move from one lattice site to another; (ii) hard disks moving on a continuum; (iii) a mixture of two sizes of nearly-hard disks moving on a continuum; (iv) a modification of (ii). The hexagons or disks represent proteins, while unocupied lattice sites or the remainder of the continuum represents lipids. In (iii) large disks represent proteins and small disks represent lipids. In (iv) some of the continuum between pairs of disks, where packing defects might occur, is not occupied by lipids. We find that an analytical expression for the adjacent lipids (Hoffmann et al. 1981), which is in excellent agreement with the results of the Hexagon model (i), breaks down at a packing density of f _A0.805, and we show by considering the hexagon pair correlation function, that this indicates the onset of random close packing, and that a transition to ordered close packing occurs at f _A=0.866. We thus obtain an operational definition for a random distribution of hexagons: distributions of packing densities0.805. We show that the Disk model (ii) gives results for adjacent lipids that are greater than the Hexagon model and compare these results to the Two Disk model (iii) which gives a result substantially less than the Hexagon model (Mountain et al. 1986). We show that the Modified Disk model (iv) gives results in essential agreement with the Hexagon model except for f _A0.77. Finally we discuss the general appearance of the motion restricted ESR spectrum and conclude that, of these four models, the Modified Disk or the Hexagon models best account for the data. We discuss why this is so with reference to the representation of a 3-dimensional membrane by a 2-dimensional plane.Abbreviations ESR Electron Spin Resonance     

The reality and evolutionary significance of human psychological sex differences

The aims of this article are: (i) to provide a quantitative overview of sex differences in human psychological attributes; and (ii) to consider evidence for their possible evolutionary origins. Sex differences were identified from a systematic literature search of meta‐analyses and large‐sample studies. These were organized in terms of evolutionary significance as follows: (i) characteristics arising from inter‐male competition (within‐sex aggression; impulsiveness and sensation‐seeking; fearfulness; visuospatial and object‐location memory; object‐centred orientations); (ii) those concerning social relations that are likely to have arisen from women's adaptations for small‐group interactions and men's for larger co‐operative groups (person‐centred orientation and social skills; language; depression and anxiety); (iii) those arising from female choice (sexuality; mate choice; sexual conflict). There were sex differences in all categories, whose magnitudes ranged from (i) small (object location memory; negative emotions), to (ii) medium (mental rotation; anxiety disorders; impulsivity; sex drive; interest in casual sex), to (iii) large (social interests and abilities; sociosexuality); and (iv) very large (escalated aggression; systemizing; sexual violence). Evolutionary explanations were evaluated according to whether: (i) similar differences occur in other mammals; (ii) there is cross‐cultural consistency; (iii) the origin was early in life or at puberty; (iv) there was evidence for hormonal influences; and (v), where possible, whether there was evidence for evolutionarily derived design features. The evidence was positive for most features in most categories, suggesting evolutionary origins for a broad range of sex differences. Attributes for which there was no sex difference are also noted. Within‐sex variations are discussed as limitations to the emphasis on sex differences.     

Interplay of Intrinsic and Synaptic Conductances in the Generation of High-Frequency Oscillations in Interneuronal Networks with Irregular Spiking

High-frequency oscillations (above 30 Hz) have been observed in sensory and higher-order brain areas, and are believed to constitute a general hallmark of functional neuronal activation. Fast inhibition in interneuronal networks has been suggested as a general mechanism for the generation of high-frequency oscillations. Certain classes of interneurons exhibit subthreshold oscillations, but the effect of this intrinsic neuronal property on the population rhythm is not completely understood. We study the influence of intrinsic damped subthreshold oscillations in the emergence of collective high-frequency oscillations, and elucidate the dynamical mechanisms that underlie this phenomenon. We simulate neuronal networks composed of either Integrate-and-Fire (IF) or Generalized Integrate-and-Fire (GIF) neurons. The IF model displays purely passive subthreshold dynamics, while the GIF model exhibits subthreshold damped oscillations. Individual neurons receive inhibitory synaptic currents mediated by spiking activity in their neighbors as well as noisy synaptic bombardment, and fire irregularly at a lower rate than population frequency. We identify three factors that affect the influence of single-neuron properties on synchronization mediated by inhibition: i) the firing rate response to the noisy background input, ii) the membrane potential distribution, and iii) the shape of Inhibitory Post-Synaptic Potentials (IPSPs). For hyperpolarizing inhibition, the GIF IPSP profile (factor iii)) exhibits post-inhibitory rebound, which induces a coherent spike-mediated depolarization across cells that greatly facilitates synchronous oscillations. This effect dominates the network dynamics, hence GIF networks display stronger oscillations than IF networks. However, the restorative current in the GIF neuron lowers firing rates and narrows the membrane potential distribution (factors i) and ii), respectively), which tend to decrease synchrony. If inhibition is shunting instead of hyperpolarizing, post-inhibitory rebound is not elicited and factors i) and ii) dominate, yielding lower synchrony in GIF networks than in IF networks.     

Effects of PCMBS on the water and small solute permeabilities in frog urinary bladder

Summary It has been reported that PCMBS (p-chloromercuribenzene sulfonate) blocks the water permeability of red cells and of the tubular kidney membranes. In this study we compare the effects of this mercurial compound on the permeability of water and other small solutes in the frog urinary bladder.We observed that: (i) 5mm PCMBS applied at pH 5.0 to the mucosal side inhibited the net and unidirectional water fluxes induced by oxytocin without changing the P _f/P _d ratio. (ii) The oxytocin-induced urea and Na⁺ influxes were also inhibited by PCMBS. (iii) The unidirectional Cl^– movement was first reduced and then increased during the course of PCMBS treatment. (iv) The short-circuit measured at low mucosal Na⁺ concentration (10mm), diminished continuously, whereas the transepithelial resistance first increased and then diminished. (v) Mannitol, raffinose, -methyl-glucose, antipyrine, caffeine and Rb⁺ movements were not changed significantly during the first 26 min of the water permeability inhibition. In conclusion: (i) The ADH-sensitive water, urea and Na⁺ transport systems were inhibited by PCMBS, (ii) PCMBS did not induce a nonspecific and general effect on the permeability of the membrane during the development of the water permeability inhibition, and (iii) in terms of water channels, the inhibition of water transport with the maintenance of a highP _f/P _d ratio suggests that PCMBS closes the water channels in an all or none manner, reducing their operative number in the apical border of frog bladder.     

Comparative study of the effects of cromakalim (BRL 34915) and diazoxide on membrane potential, [Ca2+] i and ATP-sensitive potassium currents in insulin-secreting cells

Summary Patch-clamp and single cell [Ca²⁺] _i measurements have been used to investigate the effects of the potassium channel modulators cromakalim, diazoxide and tolbutamide on the insulin-secreting cell line RINm5F. In intact cells, with an average cellular transmembrane potential of –62±2 mV (n=42) and an average basal [Ca²⁺] _i of 102±6nm (n=37), glucose (2.5–10mm): (i) depolarized the membrane, through a decrease in the outward K_ATP current, (ii) evoked Ca²⁺ spike potentials, and (iii) caused a sharp rise in [Ca²⁺] _i . In the continued presence of glucose both cromakalim (100–200 m) and diazoxide (100 m) repolarized the membrane, terminated Ca²⁺ spike potentials and attenuated the secretagogue-induced rise in [Ca²⁺] _i . In whole cells (voltage-clamp records) and excised outside-out membrane patches, both cromakalim and diazoxide enhanced the current by opening ATP-sensitive K⁺ channels. Diazoxide was consistently found to be more potent than cromakalim. Tolbutamide, a specific inhibitor of ATP-sensitive K⁺ channels, reversed the effects of cromakalim on membrane potential and K_ATP currents.     

Length of human prematurely condensed chromosomes during G0 and G1 phase

Length measurements on C-banded prematurely condensed no. 1 human chromosomes of G0 and G1 lymphocytes, as well as of synchronized G1 HEp cells revealed that (i) no length difference exists between mitotic chromosomes and G0 chromosomes; (ii) 1 h after PHA stimulation a clear increase in length is detectable; (iii) in isolated cases an increase by the factor 5 can be observed during G1; (iv) the increase is significantly less for constitutive heterochromatin than for euchromatin. The possibility is discussed that these conformational changes of chromatin reflect physiological differences, i.e. the rate of RNA synthesis during interphase.     

Dendritic properties of uropod motoneurons and premotor nonspiking interneurons in the crayfish Procambarus clarkii Girard

Dendritic properties of uropod motoneurons and premotor nonspiking interneurons of crayfish have been studied using intradendritic recording and current injection. The input resistance of phasic motoneurons (5.20 ± 0.5 M; mean ± standard error) measured by injecting constant hyperpolarizing current was significantly lower than that of tonic motoneurons (10.3 ± 2.6 M; 0.02 < P < 0.05). The membrane time constant of phasic motoneurons (7.3 ± 0.9 ms) was also significantly shorter than that of tonic motoneurons (24.3 ± 2.5 ms; P < 0.001). Both types of motoneurons behaved linearly during hyperpolarization and sub-threshold depolarization. Nonspiking interneurons showed outward rectification upon depolarization. During hyperpolarization, their membrane behaved linearly and showed significantly higher input resistance (19.5 ± 2.5 M) than phasic and tonic motoneurons (P < 0.001). Their membrane time constant (38.0 ± 5.7 ms) was significantly longer than that of phasic motoneurons (P < 0.001) but not than that of tonic motoneurons (P > 0.05). In response to intracellular injection of sinusoidally oscillating current, phasic motoneurons showed one or two spikes per depolarization period irrespective of oscillating frequency ranging from 1 to 16 Hz. Tonic motoneurons showed larger numbers of spikes per stimulus period at lower frequencies. Nonspiking interneurons also showed phase-locked effects on the motoneuron spike activity. The effective frequency range over which injected oscillating current could modulate motoneuron spike activity was similar for tonic motoneurons and nonspiking interneurons.     

Heterogeneity of desmin,the muscle-type intermediate filament protein,in blood vessels and astrocytes

Summary Monoclonal antibodies were isolated from mice immunized with chicken gizzard desmin. Antibodies reacting with desmin on immunoblots and selectively decorating chicken and rat intestinal smooth muscle as well as the Z-line in striated muscle, were selected for this study. Based on their staining pattern on cryostat sections of chicken and rat cerebellum, spleen, kidney, aorta and femoral artery, monoclonal supernatants could be divided in three groups: (i) antibodies decorating astrocytes and vascular smooth muscle; (ii) antibodies decorating only vascular smooth muscle; (iii) antibodies decorating only astrocytes. Antibodies in group (i) and (iii) also stained GFA-negative Bergmann glia in chicken cerebellum. It is proposed that desmin may vary depending on the histological localization.     

Enzymatic synthesis of ATP from RNA and adenine

Summary The title compound was prepared by a three-stage enzymatic procedure consisting of (i) RNA hydrolysis to a mixture of ribonucleosides using intact mycelium of Spicaria violacea, (ii) transribosylation of exogenous adenine employing whole cells of Escherichia coli as a biocatalyst, and (iii) conversion of formed adenosine into ATP by the enzymes of alcohol fermentation and the kinases extracted from baker's yeast.     

Studies of the cyclic adenosine monophosphate chemoreceptor ofParamecium

Summary A doublet of proteins (48,000M _r) from theParamecium cell body membrane fits several criteria for the external cAMP chemoreceptor. These criteria include: (i) selective elution from a cAMP affinity column, matching a specificity that could be predicted from the behavioral response and whole-cell binding; (ii) binding to wheat germ agglutinin indicating the presence of carbohydrate moieties indicating surface exposure; and (iii) selective inhibition of the intact cells' chemoresponse to cAMP by antibodies against the doublet. Additional evidence for the existence of a receptor, in general, comes from selective elimination of the cAMP chemoresponse by photoaffinity labeling of whole cells with 8-N₃-cAMP. The doublet proteins are not identical to the regulatory subunit of a cAMP-dependent protein kinase fromParamecium, theDictyostelium cAMP chemoreceptor, or the 42–45 kDa range proteins related to the large surface glycoprotein inParamecium. The doublet proteins are not readily separable and, as inDictyostelium, may represent two different covalent modification states of the same protein. Amino acid analysis indicates that the proteins are similar, but does not distinguish between the possibilities of proteolysis and covalent modification. Once cloned, this doublet may prove to be only the fifth external, eukaryotic chemoreceptor to be identified.     

Rethinking anaphase: where “Pac-Man” fails and why a role for the spindle matrix is likely

Summary The Pac-Man model for explaining chromosome movement is based on three main tenets: (i) the force that moves chromosomes is generated at the kinetochore; (ii) disassembly of the microtubules (MTs) of the kinetochore fibre generates poleward movement; and (iii) the energy required for this movement comes from MT disassembly. We show that these tenets are not valid in some and perhaps many situations. Thus, the Pac-Man model is inadequate and misleading as the central basis for explaining chromosomal motion generally. We argue that multiple mechanisms are involved in mitotic function and that a contractile/elastic spindle matrix is likely involved not only in anchoring kinetochore fibres, but also by exerting force on them. This view of the spindle matrix shares some features with the tensegrity model already formulated as a basis for understanding interphase cell behaviour.     

A neural network model for limb trajectory formation

This paper deals with the problem of representing and generating unconstrained aiming movements of a limb by means of a neural network architecture. The network produced time trajectories of a limb from a starting posture toward targets specified by sensory stimuli. Thus the network performed a sensory-motor transformation. The experimenters trained the network using a bell-shaped velocity profile on the trajectories. This type of profile is characteristic of most movements performed by biological systems. We investigated the generalization capabilities of the network as well as its internal organization. Experiments performed during learning and on the trained network showed that: (i) the task could be learned by a three-layer sequential network; (ii) the network successfully generalized in trajectory space and adjusted the velocity profiles properly; (iii) the same task could not be learned by a linear network; (iv) after learning, the internal connections became organized into inhibitory and excitatory zones and encoded the main features of the training set; (v) the model was robust to noise on the input signals; (vi) the network exhibited attractor-dynamics properties; (vii) the network was able to solve the motorequivalence problem. A key feature of this work is the fact that the neural network was coupled to a mechanical model of a limb in which muscles are represented as springs. With this representation the model solved the problem of motor redundancy.     

Functional abnormalities in iPSC‐derived cardiomyocytes generated from CPVT1 and CPVT2 patients carrying ryanodine or calsequestrin mutations

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia characterized by syncope and sudden death occurring during exercise or acute emotion. CPVT is caused by abnormal intracellular Ca²⁺ handling resulting from mutations in the RyR2 or CASQ2 genes. Because CASQ2 and RyR2 are involved in different aspects of the excitation‐contraction coupling process, we hypothesized that these mutations are associated with different functional and intracellular Ca²⁺ abnormalities. To test the hypothesis we generated induced Pluripotent Stem Cell‐derived cardiomyocytes (iPSC‐CM) from CPVT1 and CPVT2 patients carrying the RyR2^R420Q and CASQ2^D307H mutations, respectively, and investigated in CPVT1 and CPVT2 iPSC‐CM (compared to control): (i) The ultrastructural features; (ii) the effects of isoproterenol, caffeine and ryanodine on the [Ca²⁺]_i transient characteristics. Our major findings were: (i) Ultrastructurally, CASQ2 and RyR2 mutated cardiomyocytes were less developed than control cardiomyocytes. (ii) While in control iPSC‐CM isoproterenol caused positive inotropic and lusitropic effects, in the mutated cardiomyocytes isoproterenol was either ineffective, caused arrhythmias, or markedly increased diastolic [Ca²⁺]_i. Importantly, positive inotropic and lusitropic effects were not induced in mutated cardiomyocytes. (iii) The effects of caffeine and ryanodine in mutated cardiomyocytes differed from control cardiomyocytes. Our results show that iPSC‐CM are useful for investigating the similarities/differences in the pathophysiological consequences of RyR2 versus CASQ2 mutations underlying CPVT1 and CPVT2 syndromes.     

Forecasting non-stationary diarrhea, acute respiratory infection, and malaria time-series in Niono, Mali

Background

Much of the developing world, particularly sub-Saharan Africa, exhibits high levels of morbidity and mortality associated with diarrhea, acute respiratory infection, and malaria. With the increasing awareness that the aforementioned infectious diseases impose an enormous burden on developing countries, public health programs therein could benefit from parsimonious general-purpose forecasting methods to enhance infectious disease intervention. Unfortunately, these disease time-series often i) suffer from non-stationarity; ii) exhibit large inter-annual plus seasonal fluctuations; and, iii) require disease-specific tailoring of forecasting methods.

Methodology/Principal Findings

In this longitudinal retrospective (01/1996–06/2004) investigation, diarrhea, acute respiratory infection of the lower tract, and malaria consultation time-series are fitted with a general-purpose econometric method, namely the multiplicative Holt-Winters, to produce contemporaneous on-line forecasts for the district of Niono, Mali. This method accommodates seasonal, as well as inter-annual, fluctuations and produces reasonably accurate median 2- and 3-month horizon forecasts for these non-stationary time-series, i.e., 92% of the 24 time-series forecasts generated (2 forecast horizons, 3 diseases, and 4 age categories = 24 time-series forecasts) have mean absolute percentage errors circa 25%.

Conclusions/Significance

The multiplicative Holt-Winters forecasting method: i) performs well across diseases with dramatically distinct transmission modes and hence it is a strong general-purpose forecasting method candidate for non-stationary epidemiological time-series; ii) obliquely captures prior non-linear interactions between climate and the aforementioned disease dynamics thus, obviating the need for more complex disease-specific climate-based parametric forecasting methods in the district of Niono; furthermore, iii) readily decomposes time-series into seasonal components thereby potentially assisting with programming of public health interventions, as well as monitoring of disease dynamics modification. Therefore, these forecasts could improve infectious diseases management in the district of Niono, Mali, and elsewhere in the Sahel.